Locking device



March 11, 1930. w. F. ZIMMERMANN' 1,750,340

LOCKING DEVICE Filed March 23, 1928 Z FT 0 E W D E H V 2; ,3 Z Y m u; V

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INVENTOR.

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Patented Mar. 11, 1930 UNITED STATES PATENT OFFICE WILLIAM FRANK ZIMMERMANN, OF VVAVERLY, NEW YORK, ASSIGNOR TO INGERSOLL- RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY LOCKING DEVICE Application filed March 23, 1928.

This invention relates to pneumatic tools, but more particularly to a locking device for pneumatic tools of the type in which the tool handle is secured to the cylinder by means of screw threads.

The objects of the invention are to maintain a tight connection between the casing parts of pneumatic tools, such as chipping hammers, riveters and the like, and to enable the connection to be conveniently tightened whenever it becomes loosened through wear.

Other objects will be in part obvious and in part pointed out hereinafter.

In the accompanying specification in which similar reference characters refer to similar parts,

Figure l is a sectional elevation of a portion of a pneumatic tool having the invention applied thereto,

Figure 2 is a transverse view taken through Figure 1 on the line 22 looking in the direction indicated by the arrows, and

Figure 3 is a perspective view of the locking device and the elements adapted to be locked together.

Referring to the drawings, A designates the cylinder of a pneumatic tool, B the piston reciprocable in the cylinder and C the handle whereby the tool may be manipulated.

The handle C in this instance has an extension D in the form of a hood having an internal threaded portion E to receive an externally threaded portion F on the rearward end of the cylinder A. In order to centralize the extension D on the cylinder A, said extension is preferably provided with a plain cylindrical internal surface G in its front end to slidably receive a smooth cylindrical surface H of the cylinder.

Pressure fluid for actuating the tool is admitted through a passage J extending through the handle C and communicating at its inner end with a pressure chamber K in the rearward end or wall D of the extension D. The distribution of pressure fluid to the cylinder for actuating the piston B may be effected by suitable valve mechanism, only the exterior of the valve box L of which is 50 shown, said valve box L being located in an Serial No. 264,127.

enlarged bore 0 in the rearward end of the cylinder A.

The valve box may consist of one or more parts, two being shown in the drawings, and its total length preferably exceeds somewhat that of the bore in which it is disposed. In this way the wall D may bear against the end of the valve box L when the handle is screwed on the cylinder A for clamping the valve box L firmly in the bore 0.

The admission of pressure fluid from the chamber K into the valve box L is effected through supply passages P in the rearward end of the valve box. Pressure fluid may be admitted into the rearward end of the cylinder for impelling the piston B forwardly through suitable passages (not shown) but which may be located in the front end of the valve box to establish direct communication between that end of the valve box and the end of the cylinder. An inlet passagev Q leads from the bore O to the front end of the cylinder. I V

In the construction shown, the pressure fluid utilized for actuating the piston B may again be conveyed through the inlet passages and the valve box, thence through an exhaust passage R leading from the bore 0 to the exterior of the cylinder A.

As is well known, tools of the type to which the present invention is applied are subjected to severe vibration and shocks during their operation and considerable difliculty is at times experienced inmaintaining tight connections between the various elements of the tool. This is more often the case with respect to the casing parts, such as the cylinder A and the handle G, particularly where the handle is threaded on the cylinder as in the present instance. During the assembly of the tool, these parts are screwed tightly to gether but, due to the rough usage which they receive, the handle at times becomes partly unscrewed. If this condition is not detected immediately, the relative longitudinal movement of the handle and the cylinder, caused by vibration, will ruin the threaded connection and the cooperating surfaces of the valve box L, the handle G and the bore 0.

Another difiiculty frequently experienced is that when the valve structure, such as the valve box L, is clamped in the cylinder by means of the handle, any clearance formed by the unscrewing of the handle on the cylinder will of course allow the valve box to vibrate in the bore 0. Such movement of the valve box will effect the efficient functioning of the valve and consequently of the reciprocatory elements of the tool.

The present invention contemplates the provision of means for assuring a tight connection between the cylinder A and the h andle B. To this end the extension D is provided with a lug S which projects forwardly of the extension and. forms a seat or abutment for an end E of a spring U. The spring U is in the form of a ring, the inner diameter of which is preferably of such size as to enable the spring U to fit snugly on the cylindrical surface H of the cylinder. An abutment is provided for the opposite end V of the spring U by a lug formed on the end of a ring X, which, like the spring U, is also adapted to be disposed on the cylindrical surface H of the cylinder. In the assembled v positions of the extension D and the ring A, the lugs S and IV of these elements will lie in substantially the same transverse plane.

The ring X not only serves as an abutment for one end of the spring U but also serves as a means for setting up a tension in the spring U. The ring X accordingly is provided on its internal surface with a plurality of grooves Y adapted to register with and of the same formation as the longitudinal grooves Z formed in the cylindrical surface H of the cylinder. Preferably the grooves Z in the cylinder slightly exceed in number the grooves Y so that only a slight rotative movement of the ring X will be required in order to bring one groove Y into registry with one of the grooves Z in the cylinder.

In the construction shown, the grooves Y and Z are of semi-cylindrical formation to accommodate a pin 6 whereby the ring X may be keyed to the cylinder. It is to be understood, however, that the groove may be of any form to accommodate a pin of different cross sectinal form from that disclosed.

Encircling the ring X and the spring U is a cover 0 which forms a casing for these elements. The cover 0 is in the form of a spring ring and may be of sufficiently smaller diameter than the front end of the extension D to enable said cover, due to its resiliency, to tightly engage the front end of the extension D. On the front end of the cover is an inwardly extending flange (Z which forms a seat for the front end of the ring X and the pin 5, and also bears against an exhaust deflector which embraces the cylinder A and communicates with the passage It to receive the exhaust fluid therefrom.

The front end f of the deflector e abuts a shoulder g on the cylinder A to hold said deflector aganist forward movement on the cylinder A. The deflector 6, like the cover 0, may also be split and is adapted to tightly engage the portion of the cylinder A whereon it is disposed.

As will be observed, ends T and V of the spring u are slightly offset with respect to each other so that when the parts are in their assembled positions, said spring will exert a pressure in a longitudinal direction on the ring X to maintain the ring firmly against the flange d and, acting through the ring, to hold the cover 0 and the deflector against endwise movement.

In assembling the device the handle C is first threaded tightly on the cylinder A. The spring U may then be placed in position so that its end T abuts the lug S of the extension D. Thereafter the ring X is placed on the cylindrical portion I-I so that the lug of said ring will form an abutment for the end V of the spring U.

In order to set up a tension in the spring U, the ring X may be rotated in the direction necessary to produce this effect. After the desired tension has been set up in the spring U, the pin 6 may be inserted into a pair of registering grooves Y and Z to lock the ring S in position. After the casing parts and the locking elements have been assembled, the cover 0 and the exhaust deflector 6 may be attached to the tool where they will be firmly held due to the inherent resiliency of these elements, as well as by the pressure of the spring U.

The spring U, as will be observed, is of substantial cross sectional area and is capable of exerting a considerable pressure for tightening the connection between the handle C and the cylinder A. After these elements have once been assembled and the proper tension is set up in the spring U, further adjustment should not be required as the handle C will remain tightly screwed on the cylinder A. However, any wear that should occur between the cooperating threaded portions of the front head and the cylinder will be automatically taken up by the spring U. In this way a tight connection will be constantly maintained between the handle and the cylinder and the valve box L will be clamped tightly in position in the bore 0 unaffected by the vibration in the tool.

I claim:

1. In a pneumatic tool, the combination of a cylinder and a handle threaded on the cylinder, a plurality of longitudinal grooves in the periphery of the cylinder, an exhaust deflector embracing the cylinder, 3. ring on the cylinder having longitudinal grooves to register with the grooves in the cylinder, a pin inserted in a pair of registering grooves to hold the ring against rotation with respect to the cylinder, lugs on the handle and the ring lying in the same transverse plane, a

cover encircling the ring, a flange on the cover interposed between the ring and the exhaust deflector, and a tension spring encircling the cylinder and having ends bearing on the lugs to tighten the connection between the handle and the cylinder, said ends being offset with respect to each other to enable the spring to exert a pressure in a longitudinal direction for holding the guard and the exhaust deflector against endwise movement on the cylinder.

2. In a pneumatic tool, the combination of a cylinder and a handle threaded on the cylinder, a plurality of longitudinal grooves in the periphery of thecylinder, a ring rotatably mounted on the cylinder and having longitudinal grooves in the inner surface thereof to register with the grooves in the cylinder, a pin inserted in a pair of registering grooves to hold the ring against rotation with respect to the cylinder, lugs on the handle and the ring lying in the same transverse plane, a tension spring encircling the cylinder and having ends bearing on the lugs to tighten the connection between the handle and the cylinder, said spring overlying the grooves in the ring to prevent endwise movement of the pins in one direction, a cover encircling 'the ring and the spring, and a flange on the cover forming a seat for the ring and the pin.

In testimony whereof I have signed this specification.

WILLIAM F. ZIM'MERMANN. 

